Resin composition for a moisture absorbing film, moisture absorbing film for a package, and preparation method thereof

ABSTRACT

The present invention relates to a resin composition for moisture absorbing film comprising polyethylene resin and polyacrylic acid partial sodium salt (PAPSS) or attapulgite synthesized acrylic amide (ATPGAA) as a moisture absorbent, moisture absorbing film for packaging, and a method for manufacturing film, and the present invention also relates to a resin composition for seasoned layer packaging film to be used for maintaining the high quality of the merchandize with good taste and tissue dryness.

CROSS-REFERENCES TO RELATED APPLICATION

This patent application is a Continuation-In-Part application ofPCT/KR2011/001086 filed on Feb. 18, 2011, and the contents of which areincorporated herein by reference in its entirety. This patentapplication claims the benefit of priority from Korean PatentApplication No. 10-2013-0007363 filed on Jan. 23, 2013, the contents ofwhich are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a resin composition for a moistureabsorbing film, to a moisture absorbing film for a package, and to amethod for manufacturing same, the resin composition comprisingpolyethylene resin and polyacrylic acid partial sodium salt (PAPSS) orattapulgite synthesized acrylic amide (ATPGAA) as a moisture absorbent.

2. Description of the Related Art

According to the recent development of modern industry, diversificationand merchantability of products are considered to be important. Inproducing, storage, distribution and sale of products, the need ofconsumer is growing in packaging, handling and quality preservation.

Therefore, there is active research effort in the field of packagingindustry to improve marketability of products to give functionalfactor(s) and to provide activities into the products by packaging, awayfrom the simple purpose of protection of the packaging product andquality maintain.

Nowadays, plastic packaging has actively developed to the packaging offoods, medicines, electronics and household goods due to thelightweight, excellent gas barrier properties, transparency, andrelatively low cost.

Functional packaging materials in recent research mostly are produced bymethod such as impregnation and coating with active substances forimproving quality of products, which is for providing constantly theproducts with maximum effect right after packaging. For example, therehave been attempts to develop films such as nano-film for increasingmoisture and gas barrier properties, film comprising zeolite forinhibiting growth of microorganisms of the products, far infraredradiation film emitting energy, off-flavor-adsorptive film, and oxygenand/or off-flavor gas-adsorptive film.

If food is moisture sensitive, there is a need to remain dry inside thepackaging. Because water activity is one of the factors to induce changeof the physical properties of product, occurrence of the rancidity, lossof the nutritional value, decrease of sensual properties, and fooddeterioration through microbial growth. Water activity may be also oneof the factors to decrease the quality of the packaged products byinducing oxidation corrosion of a metal surface in the electronicproducts.

In order to solve these problems, food is typically treated with hotair-drying pretreatment, drying gas substitution packaging, blockablevacuum packaging, desiccant addition to inside the packaging and thelike. However, these methods are disadvantageous including inconvenientprocess, increased cost, weakening of drying durability throughincreasing storage period.

Desiccant is one of substances used to remove the moisture from thematerial to be dry. It reacts with water, and eliminates it by achemical action of adhering moisture, or by a physical action ofwater-adsorption or water-absorption, separately. Typical desiccants bya chemical action of removing moisture are calcium chloride or coppersulfate and these shall absorb moisture in the form of crystal water.Typical desiccants by a physical action of removing moisture aresilica-gel, aluminium oxide, zeolite, and the like, and these are ableto accommodate a large amount of moisture in the large surface area ofthe material.

As one of these desiccants, silica-gel is a granular mineral material ofsilicon dioxide (SiO₂). The average pore size of silica-gel as adesiccant is 24 Å, and has a high affinity with water molecules.Silica-gel has a property to pull moisture until 220° F. (105° C.), showmaximum activity as a desiccant in the range of 70° F.˜90° F., 60˜90%RH, and absorb moisture by 40% RH. It is an only approved material inthe FDA (U.S.A.) which can directly contact with foods and medicines.

Silica-gel can absorb many organic chemical materials with various poresizes other than moisture. The silica-gel's absorbable chemicalmaterials and the order of absorbability follow: water, ammonia,alcohols, aromatics, diolefins, olefins, and paraffins.

As an another desiccant, molecular sieve is a synthetic porousaluminosilicate having strong moisture-adsorbing capacity. Other thanother desiccants, the adsorbing pores of it are uniformed and latticestructured. The size of the adsorbing pores can be controlled. Ingeneral, materials having 3 Å, 4 Å, 5 Å, 10 Å adsorbing pores are used.

Molecular sieve can adsorb water, but emit volatile substances. In caseof 3 Å, water can be adsorbed and many hydrocarbons can be emitted. Incase of 4 Å, the adsorption capacity is superior than that of 3 Å,however emits more buthane. It can contain moisture up to 230° C. (450°F.) and maintain 10% RH as having better moisture adsorbing capacitythan silica-gel. The FDA has approved sodium aluminosilicate for directcontact with consumable items, and Europe had used molecular sieves withpharmaceuticals. It is expensive, however adsorption capacity isexcellent, and thus it is generally used to maintain low humiditycondition.

As the other desiccant, montmorillonite (MMT) clay is prepared by dryingmagnesium aluminum silicate in a form of sub-bentonite. If there is notany contamination and swelling, MMT once used under low humiditycondition can be re-cycled. It has showed the reverse effect ofre-emission water after absorbing it. MMT performs the desiccantfunction in the condition of 120° F. (50° C.) or less while it emitswater rather than absorbing in the condition of 120° F. (50° C.) above.Therefore, when MMT is used as a desiccant, it is needed to consider theconditions of storage and distribution. In general, the standardrelative humidity at room temperature, it fully functions as adesiccant. The color of MMT particle is gray, and the purity thereofshould be increased to minimize the reaction with the packagingproducts.

Calcium oxide (CaO) can absorb water up to 28.5 wt % of its own weight.Since the CaO has excellent absorbing capacity among the desiccants, itis used when the condition of maintaining low humidity is veryimportant. CaO absorbs moisture at a slow pace, and swells by theabsorbed moisture. In case of dry-frozen food, the use of CaO islimited.

The desiccants such as CaO, zeolite, silica-gel have been used in theway of putting one of them in a Tyvek pouch, sealing the pouch andapplying it into food packages.

The basic objects of using desiccants are to maintain the originaltexture of the products and to block any microbial growth in them. Incase of fruits, desiccants by adjusting saturated humidity conditions infruit packages are used to prevent the package inside from producingwater droplets due to the water vapors of fruit transpiration.

Salts, saturated salt solution, superabsorbent polymer can be mainlyused as a desiccant, and superabsorbent polymer sheet usually is used inmeat or fish products to absorb meat or fish broth produced depending onthe temperature. Polyacrylate or starch graft polymer is mainly used asthe sheet material. In these cases, packaging products incorporatedhuectant between the plastic films, such as propylene glycol (film)sealing with polyvinyl alcohol, can be used for the purpose of coveringmeat or fish. It also can be applied variously to protect electronicproducts or components, and metal/electrical, electronic precisionmachines by the prevention of rusting/corrosion may occurred from themoisture while their storage and transportation.

Desiccants are widely used to maintain the quality of food, medicine,electronic product and the like. The desiccant is usually used as a formof small pouch and packaged together with the product inside thepackaging. Thus there may be some concerns occurred such as thecontamination of food or decreasing the quality of the products by thespilled desiccant when the pouch has deficiencies in packaging, and theadverse effects can go further to the consumers' safety when thedesiccant is used in the food or medicine.

Also, the process of putting desiccant pouches into the product isinconvenient, and it is highly possible to produce off-flavor and/orreactants after the desiccant adsorb the moisture.

Therefore, the inventors of the present invention were intended todevelop a functional adsorbing packaging film for moisture-sensitiveproducts with the consideration of handy uses and long lasting effect ofmoisture-adsorption. After investigating various desiccants, selectedapplicable desiccants with high moisture-adsorption activity, andprepared samples to be analyzed in a desiccant impregnated form into theplastic films by concentration of the desiccant. Physical properties andfunctional adsorption effect of the impregnated film were tested.

As a result, the present invention is completed by identifying to beable to manufacture a moisture adsorbing film providing excellentmoisture adsorbing capability and good physical properties when the filmis manufactured from polyethylene resin impregnated with polyacrylicacid partial sodium salt (PAPSS) or attapulgite synthesized acrylicamide (ATPGAA).

The present invention also provides film with resin composition to beused conveniently and having a long lasting-adsorption capacity forpackaging moisture-sensitive dried food such as layer.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to provide a resincomposition and its manufacturing method for a moisture absorbing filmhaving superior capability for absorbing moisture and sustaining theeffect, and also having excellent physical properties for nocontamination causing to the merchandize and its handy uses.

The another purpose of the present invention is to provide a resincomposition for seasoned layer packaging film having superior capabilityto maintain high quality of packaged seasoned layer by removing theabsorbed internal moisture of the packaged film.

Following to a formulation of the present invention, it provides to aresin composition for a moisture absorbing film comprising polyethyleneresin, and polyacrylic acid partial sodium salt (PAPSS) or attapulgitesynthesized acrylic amide (ATPGAA) as a moisture absorber.

Polyacrylic acid partial sodium salt (PAPSS) is a superabsorbent productprocessed crosslinking with sodium salts and polyacrylic acid (PA). ThePAPSS can process absorbing activities by containing moisture in themolecular spaces formed in the molecular chains of the PAPSS through thecross-linking processes.

The PAPSS is the product processed lesser degree of the crosslinkingthan polyacryic acid sodium salts (PASS). The PASS is the productprocessed the crosslinking more than PAPSS.

PAPSS is non-toxic and alkaline. PAPSS rapidly melts when it contactswith water directly and increases its volume. The powder type PAPSScondenses when it is contacted with water or high humidity (FIG. 1) andit melts in water when the moisture quantity increases. It can be usedat a high concentration. The PAPSS has a chemical property to bedistributed to various salts, and so, is used for manufacturing papersand pigments, or for plant air-controlling systems.

The structural formula of PAPSS is C₃H₃NaO₂, and it is used for medicalappliance. When PAPSS is used for medical appliance, it can be used toanti-viral material, such as agents for preventing and treatinganti-tumor and viral disease, or agent for interfering DNA synthesis ofvirus. Also, PAPSS is used for medical devices (implants, prosthetics)for dental clinic, and a component of eye drops. It is reported thatmoisture absorbency decreases when the proportion of cross-linked saltincreases.

Attapulgite synthesized acrylic amide (ATPGAA) is cross-linked materialwith attapulgite (ATPG) and poly acrylamide (AA). It is a hybrid productby synthesizing inorganic and organic material according to JunpingZhang (2007).

Attapulgite is classified as a clay group such as zeolite,montmorillonite (MMT), and diatomite. It consists of mainly magnesiumaluminium phyllosilicate, (Mg,Al)₂Si₄O₁₀(OH).4(H₂O), fuller's earth,smectite, and palygorskite.

Smectite is formulated by a lattice structure, and the latticestructured particles and moisture are combined through hydrogen bonding,and it presents in the form of gel. Palygorskite is neither expanded norextended. Palygorskite particles are considered to be charged with thezones of + and − charges, and attapulgite is changed to the gel type insolution.

Attapulgite has already been used for paints, sealants, adhesives,catalysts, fixing agents, and binders. It is less expensive than othernano-sized clays.

Studies for attapulgite synthesized acrylic amide (ATPGAA) have beingconducted to apply the polymer for advanced technology. The studiesidentified that the ATPGAA showed excellent moisture absorbingperformance when it was synthesized after replacing surface ofattapulgite with ions.

This material was developed to be first applied as pot fillers ofornamental trees, and progressed to the other applications as theresearches went further.

Polyacrylic amide as a polymer, cannot be ionized and is one of highlyswelling water-soluble synthetic polymers. It has excellent physicalproperties composed through cross-linking.

Through the synthesis process of saponification, the surface ofsynthesized ATPGAA can be improved. The synthesis process of ATPGAAaccording to example one is shown in FIG. 2.

According to the present invention of the resin composition for moistureabsorbing film, the preferable weight ratio of moisture absorbent tototal resin composition is 0.5 to 4 wt %.

According to the present invention of the resin composition for moistureabsorbing film, the preferable polyethylene resin is linear low densitypolyethylene (LLDPE),

According to the present invention of the resin composition for moistureabsorbing film, preferable melting point of the polyethylene resin islower than 180° C. It is due to when the processing temperature is above180° C., polyacrylic acid partial sodium salt can be thermallydecomposited.

According to another formulation of the present invention, the presentinvention provides moisture absorbing film characterized for packagingwhen the film was manufactured following to the resin composition.

According to one other formulation of the present invention, the presentinvention provides a manufacturing method for moisture absorbing filmcharacterized for packaging, which includes the processes of preparingpallets by compounding polyethylene resin and a moisture absorber,adding further polyethylene resin to the pallets, and blow-extrusingthem. Wherein, the moisture absorbent is characterized to be chosen frompolyacrylic acid partial sodium salt (PAPSS) or attapulgite synthesizedacrylic amide (ATPGAA).

In the step of manufacturing pallets, the preferable weight ratio ofpolyethylene resin to moisture absorbent is 20:1 to 20:6, and it ispreferable to add polyethylene resin further to the composition in thestep of blow-extrusing, to give the weight ratio of PAPSS to total resincomposition is 0.5 to 4 wt %. More preferably, in the step ofmanufacturing pallets, the weight ratio of polyethylene resin tomoisture absorbent is 9:1.

According to the present invention, the preferable grain size ofmoisture absorber is 100 to 500 mesh.

The present invention provides manufacturing a film having superiormoisture absorbing performance and excellent physical properties.

The present invention also provides a resin composition for seasonedlayer packaging film to be used for maintaining the high quality of themerchandize with good taste and tissue dryness by removing the internalmoisture and offensive off-flavor in the seasoned layer packages.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts the swelling behavior of 5 g PAPSS, according to theaddition of water 10 mL (left), 50 mL (middle), and 100 mL (right).

FIG. 2 depicts the synthesizing procedure for ATPGAA.

FIG. 3 depicts the experimental procedure.

FIG. 4 depicts the sorption behavior of sample materials at 20° C., 30°C., 40° C.

FIG. 5 depicts the pictures showing the distribution of PAPSS particlesin the sheet made with 2.5× dispersing agent (Triton X-100).

FIG. 6 depicts the pictures showing the distribution of PAPSS particlesin the sheet made with 2.0× dispersing agent (Triton X-100).

FIG. 7 depicts the mechanical properties of the sheet.

FIG. 8 depicts the flow chart showing the manufacturing procedures forthe packaging film of present invention.

FIG. 9 depicts the sorption behavior of sample materials following tothe present invention by the concentration of absorbents.

FIG. 10 depicts the moisture distribution ratio by the concentration ofabsorbents.

FIG. 11 depicts the mechanical properties of the film by theconcentration of PAPSS.

FIG. 12 depicts the mechanical properties of the film by theconcentration of ATPGAA.

FIG. 13 depicts the peroxide value (PV) of seasoned layer sample at 23°C.

FIG. 14 depicts the peroxide value (PV) of seasoned layer sample at 40°C.

FIG. 15 depicts the peroxide value (PV) of seasoned layer sample at 60°C.

FIG. 16 depicts the absorbance peak range change from 1800 cm⁻¹ to 1700cm⁻¹ during the storage period at 23° C.

FIG. 17 depicts the absorbance peak range change from 1800 cm⁻¹ to 1700cm⁻¹ during the storage period at 40° C.

FIG. 18 depicts the absorbance peak range change from 1800 cm⁻¹ to 1700cm⁻¹ during the storage period at 60° C.

FIG. 19 depicts the fragility (crispness) of seasoned layer sample at23° C.

FIG. 20 depicts the fragility (crispness) of seasoned layer sample at40° C.

FIG. 21 depicts the fragility (crispness) of seasoned layer sample at60° C.

FIG. 22 depicts ΔE value of seasoned layer sample on the day 30.

FIG. 23 depicts the weight change of seasoned layer sample at 23° C.

FIG. 24 depicts the weight change of seasoned layer sample at 40° C.

FIG. 25 depicts the weight change of seasoned layer sample at 60° C.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be illustrated with the following examples.These examples are not interpreted to restrict the scope of the presentinvention.

The present invention relates to a resin composition for a moistureabsorbing film, the resin composition comprising polyethylene resin andpolyacrylic acid partial sodium salt (PAPSS) or attapulgite synthesizedacrylic amide (ATPGAA) as a moisture absorber.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is illustrated with the following experimentalexamples. These examples are interpreted not to limit the scope of thepresent invention.

The present invention is related with a resin composition for moistureabsorbing film and the resin composition comprises polyethylene resinand polyacrylic acid partial sodium salt (PAPSS) or attapulgitesynthesized acrylic amide (ATPGAA) as a moisture absorbent.

Experimental Example 1 Analysis of Sorption-Isotherm

After several absorbents were compared each other for theirmoisture-adsorptive capacities and physical properties, experimentalabsorbents were selected by the standards of adsorbing moisture orsurrounding liquids easily and the adsorption conducted physically fromthe atmosphere. The selection was made to prevent problems such asproducing unexpected byproducts by chemical bindings between moistureand the absorbent when the absorbent is applied to use in foodpackaging.

Also, absorbents requiring minimal chemical processing were selectedafter identifying their manufacturing processes. It is also to minimizethe problems may occur when it is applied for food packaging.

The substances were selected by taking into account the adoptability ofprocessing when it is applied to the film, the possibility of processingto optimum particle size for mixing with the film, cost in massproduction, and commercial availability to be purchased.

Selected materials based on the above referenced standards are in Table1.

TABLE 1 The selected materials with standards The standard for selectingmaterials Known Physical Heavy Economical Process Absorb- absorb-chemical efficiency proper- ency ing behavior treatment ties Zeolite ∘ ∘— ∘ ∘ Diatomite ∘ ∘ — ∘ (Power Dry) Montmorillonite ∘ ∘ ∘ ∘ ∘(Closite ®Na⁺) Montinorillonite ∘ ∘ ∘ ∘ ∘ (Closite ®20A) Montmorillonite∘ ∘ ∘ ∘ ∘ (Closite ®30B) PAPSS ∘ ∘ — ∘ ∘ ATPG — ∘ — ∘ ∘ ATPGAA ∘ ∘ — — ∘Silica-gel ∘ ∘ — ∘ — * PAPSS: Polyacrylic acid partial sodium salt *ATPG: Attapulgite * ATPGAA: Attapulgite acrylic amide (synthesized)

1-1. Evaluation of Sorption Capacity

Sorption capacity evaluation for total seven candidate samples includingsilica-gel as a control was conducted to determine their moistureabsorption capacity.

Zeolite was obtained from AK Chem. Tech. Co. (APNC20, Dae-Jeon, Korea),diatomaceous earth (Powder-Dry for the trade name) was obtained fromSae-Nam materials Co. (Kyung-Nam, Korea). Montmorillonite (MMT) wassupplied from Southern clay Co. (Gonzales, Tex., USA) and Closite Na⁺was used from pre-experiment of moisture absorbency among these MMTtypes.

Polyacrylic acid partial sodium salt (PAPSS) (lightly cross linked) wasobtained from Aldrich Co., (USA) and attapulgite (ATPG) was obtainedfrom BASF Co. (Korea). Attapulgite synthesized acrylic amide (ATPGAA)was synthesized at the laboratory and the synthesis procedure thereofwas shown in FIG. 2. Silica-gel was obtained from Duk-san Co.

Zeolite is the substance of which has been improved its gas adsorptioncapacity by replacing anion on the surface with cation. Power dry is oneof diatomaceous earths, and obtained from precipitated in CaO and driedafter calcinating at 800° C. Closite Na⁺ is a natural MMT, and PAPSS isa substance contained in the middle layer of diapers. ATPG is aninorganic substance of hydrated alumina magnesium and has adsorptioncapacity. ATGAA is a substance of super-adsorption capable. Finallysilica-gel is a representative adsorption substance being applied forfood packaging, which was used as a control in the present experimentalexamples.

The sorption-isotherm experiments were carried out at different humidityconditions. Weighed 5 g of pretreated substance using digital balance(Sartorius Ag Gottingen CP224S, ±0.0001 g) and placed in the AL dishesfor one-use. The initial weight of substance is 5 g, and the sampleswere placed at 20° C., 30° C., 40° C. for 19 days. The samples wereopened and each sample was weighed to evaluate the 19 day weightchanges. The final weight (Wf-19 days after) minus initial weight (Wi-5g) equals to the adsorbed amount of water in the atmosphere for 19 days.The (W_(f)−W_(i)) divided by the initial weight is calculated as theamount of water adsorbed by the sample 1 g.

The calculated moisture sorption of sample 1 g is shown in Equation 1.

$\begin{matrix}{{Q_{eq}\left( {g/g} \right)} = \frac{W_{f}W_{i}}{W_{i}}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

The experiment was conducted in the six air-tight containers prepared toequilibrate the fixed and constant relative humidity. The air-tightcontainers were plastic made and open-and-close capable and theconditions of internal system were shown in FIG. 3. The relativehumidity was adjusted with a series of saturated salt solutions.

The salts used in the experiments were KCl, NH₄NO₃, Na₂Cr₂O₇.H₂O, CaCl₂,NaOH and K₂SO₄ and these salts were capable to compose 30%, 40%, 50%,60%, 70%, and 80% relative humidity (RH). The RH difference by thestorage temperatures of these saturated salt solutions was available.Datalogger sensor (SK-Sato, SK-L200THII, Tokyo, Japan) was used tomeasure the actual RH in the internal system as FIG. 3. The actual RHmeasured by temperature was shown in Table 2.

TABLE 2 type of Water Activity (aw) salts 20° C. 30° C. 40° C. K₂SO₄0.309 0.321 0.340 KCl 0.384 0.381 0.386 NH₄NO₃ 0.514 0.558 0.614Na₄Cr₂O₇•H₂O 0.610 0.729 0.866 CaCl₂ 0.731 0.821 0.929 NaOH 0.879 0.9340.977

Temperature only was adjusted by using a large constant humidity andtemperature chamber. Three conditions, 20° C.±0.5° C., 30° C.±0.5° C.,40° C.±0.5° C. were set by assuming room temperature, outsidetemperature in summer, and storage warehouse temperature in summer,respectively. These conditions describe the storing environments of thedry products to be applied finally. Temperature effect on the adsorptioncapacity of the substances was investigated.

1-1. Results and Interpretation

Each quantity of moisture absorption by selected material was obtainedby the above equation 1, and the results were plotted in FIG. 4.

PAPSS showed the highest sorption capacity among the seven (7) materialsas shown in FIG. 4, and ATPGAA was next. Each material sorption capacityby temperature are shown in Tables 3 and Table 4.

TABLE 3 Qeq(g/g) tem.(° C.) aw Silica-gel zeolite Power Dry Closite ®Na⁺20° C. 0.3090 0.0589 ± 0.0206 0.0527 ± 0.0115 0.1206 ± 0.0092 0.0793 ±0.0008 0.3840 0.1007 ± 0.0004 0.0620 ± 0.0009 0.1371 ± 0.0027 0.0804 ±0.0042 0.5140 0.2653 ± 0.0003 0.2066 ± 0.0019 0.2000 ± 0.0037 0.1073 ±0.0034 0.6100 0.2570 ± 0.0013 0.1595 ± 0.0020 0.1529 ± 0.0503 0.0984 ±0.0038 0.7310 0.2580 ± 0.0099 0.1983 ± 0.0032 0.1798 ± 0.0026 0.1067 ±0.0050 0.8790 0.2604 ± 0.0212 0.3848 ± 0.0081 0.2779 ± 0.0043 0.1785 ±0.0093 30° C. 0.3210 0.0709 ± 0.0010 0.0442 ± 0.0006 0.1361 ± 0.00360.0556 ± 0.0008 0.3810 0.0837 ± 0.0005 0.0557 ± 0.0008 0.1417 ± 0.00680.0611 ± 0.0005 0.5580 0.2528 ± 0.0013 0.1881 ± 0.0022 0.1425 ± 0.08690.0824 ± 0.0007 0.7294 0.2126 ± 0.0028 0.1147 ± 0.0067 0.1746 ± 0.00510.0684 ± 0.0023 0.8210 0.2430 ± 0.0043 0.1940 ± 0.0015 0.1361 ± 0.00390.0813 ± 0.0035 0.9341 0.2630 ± 0.0015 0.3830 ± 0.0086 0.2762 ± 0.00490.1337 ± 0.0058 40° C. 0.3397 0.0841 ± 0.0092 0.0350 ± 0.0010 0.1531 ±0.0017 0.0295 ± 0.0034 0.3856 0.0649 ± 0.0027 0.0487 ± 0.0005 0.1467 ±0.0028 0.0398 ± 0.0077 0.6140 0.2391 ± 0.0037 0.1678 ± 0.0013 0.0792 ±0.0044 0.0551 ± 0.0313 0.8658 0.1638 ± 0.0503 0.0653 ± 0.0028 0.1984 ±0.0012 0.0354 ± 0.0136 0.9292 0.2264 ± 0.0026 0.1894 ± 0.0043 0.0881 ±0.0064 0.0534 ± 0.0239  .9774 0.2658 ± 0.0043 0.3811 ± 0.0015 0.2743 ±0.0054 0.0844 ± 0.0842

TABLE 4 Qeq(g/g) tem.(° C.) aw PAPSS ATPG ATPGAA 20° C. 0.3090 0.0458 ±0.0213 0.0671 ± 0.0156 0.0667 ± 0.0034 0.3840 0.1301 ± 0.0122 0.0824 ±0.0066 0.1241 ± 0.0077 0.5140 0.9083 ± 0.0018 0.1431 ± 0.0186 0.5150 ±0.0313 0.6100 0.6711 ± 0.0011 0.1305 ± 0.0042 0.3502 ± 0.0136 0.73100.9347 ± 0.0043 0.1369 ± 0.0068 0.4874 ± 0.0239 0.8790 0.6202 ± 0.02020.3186 ± 0.0157 0.0333 ± 0.0842 30° C. 0.3210 0.1147 ± 0.0101 0.0707 ±0.0017 0.1091 ± 0.0068 0.3810 0.1676 ± 0.0001 0.0800 ± 0.0028 0.1442 ±0.0083 0.5580 0.8354 ± 0.0172 0.1284 ± 0.0044 0.4569 ± 0.0323 0.72940.5762 ± 0.0016 0.1053 ± 0.0012 0.3045 ± 0.0084 0.8210 0.0363 ± 0.00230.1192 ± 0.0064 0.4799 ± 0.0215 0.9341 0.9057 ± 0.0009 0.3056 ± 0.00540.1966 ± 0.0811 40° C. 0.3397 0.1906 ± 0.0036 0.0747 ± 0.0068 0.1557 ±0.0006 0.3856 0.2089 ± 0.0068 0.0772 ± 0.0083 0.1663 ± 0.0008 0.61400.7551 ± 0.0087 0.1123 ± 0.0323 0.3929 ± 0.0022 0.8658 0.4717 ± 0.00510.0777 ± 0.0084 0.2542 ± 0.0067 0.9292 0.1480 ± 0.0039 0.0996 ± 0.02150.4717 ± 0.0015 0.9974 0.2198 ± 0.0049 0.2914 ± 0.0811 0.3762 ± 0.0086

The above value represents the value under the experimental environment.A mathematical model was used to estimate the value of the conditionunder non-laboratory environment. This is an existing way used in theinterpretation of the sorption isotherm curves. The values under thenon-laboratory and other conditioned environments were estimated byfinding the most appropriate model in the existing mathematical models.The mathematical models used are shown in Table 5.

TABLE 5 Name of the model Model equation reference Chang-Prost$\text{?} = {\frac{\text{?}}{\text{?}}{\ln \left\lbrack {\frac{\text{?}}{\text{?}}\ln \text{?}} \right\rbrack}}$?indicates text missing or illegible when filed Prost et al. (1976)Modified Halsey$\text{?} = \left\lbrack \frac{\text{?}}{\text{?}} \right\rbrack$?indicates text missing or illegible when filed Iglesias and Chirife(1976) GAB $\text{?} = \frac{\text{?}}{\text{?}}$?indicates text missing or illegible when filed Van der berg and Briun(1981) Modified Oswin$\text{?} = {\text{?}\frac{\text{?}}{\text{?}}\text{?}}$?indicates text missing or illegible when filed Chen (2000) Henderson-Thompson$\text{?} = \left\lbrack {\frac{\text{?}}{\text{?}}\ln \text{?}} \right\rbrack$?indicates text missing or illegible when filed Thompson et al. (1968)White and Eiring $\text{?} = \frac{\text{?}}{\text{?}}$?indicates text missing or illegible when filed Castillo et al. (2003)Peleg

Peleg (1993) Smith

Smith (1947) Courie

Castillo et al. (2003) *Xe: the same means Qeq *a, b, c, is constant.

indicates data missing or illegible when filed

Modeling criteria were determined by the basis of coefficient ofcorrelation factor, R² value, and the selected model and the constantvalues expressed in the equation for each material were shown in Table6.

TABLE 6 The fittest Constant value temp.(° C.) Materials model R² a b c20° C. silica-gel Peleg 0.91 1.28 −0.82 −1.01 ClositeNa+ Chunge-Pfost0.89 7.09 0.00 511.34 Power Dry Modified 0.82 973.82 3.34 3.00 Halseyzeolite Peleg 0.94 0.28 9.51 0.10 PAPSS Chung-Pfost 0.89 1.48 0.00420.54 ATPG Modified 0.93 −890.99 −3.03 1.53 Halsey ATPGAA Smith 0.89−0.07 0.51 — 30° C. silica-gel Peleg 0.89 1.10 −0.63 −0.84 ClositeNa+Modified 0.88 52.71 0.17 0.53 Oswin Power Dry Modified 0.73 −5.28 0.013.83 Halsey zeolite Peleg 0.86 0.16 13.37 0.07 PAPSS Modified 0.91−55.71 −0.19 0.58 Oswin ATPG Peleg 0.96 0.73 18.87 0.10 ATPGAA Modified0.93 −15.29 −0.04 1.37 Halsey 40 ° C. silica−gel Peleg 0.74 −0.01 −2.480.24 ClositeNa+ Modified 0.83 4309.04 13.78 1.84 Halsey Power Dry Peleg0.60 48.50 258.27 0.14 zeolite Peleg 0.81 0.08 28.82 0.04 PAPSS Modified0.92 −2.64 0.00 1.73 Halsey ATPG Peleg 0.98 0.82 61.67 0.09 ATPGAA Peleg0.97 2.49 36.68 0.30

By using the above Table 6, the amount of adsorbed water for the appliedmaterial at the corresponding temperature can be estimated by theprobability of R² value when the major temperatures of applied materialsare known.

The PAPSS and ATPGAA showed excellent moisture absorbencies among theseven (7) absorbents. The PAPSS and ATPGAA showed about six (6) and four(4) times superior compared to the control, silica-gel, respectively.

The modeling used in the present experimental examples deduced thelogical method to estimate the absorbencies of the substances in thefull range of relative humidity and the basis of determining the amountof substances by the products to be applied. The films were actuallymanufactured based on the above results.

Experimental Example 2 Analysis of Film Applicability by ManufacturingSheet

Two materials, PAPSS and ATPGAA, were selected through the aboveexperimental example 1. A study was conducted to apply for them inpackaging. First, the sheet was manufactured using one of universalplastic, LDPE resin, and evaluation analysis for physical properties anddistribution of material were conducted. The possibility of developingthe film was estimated by manufacturing the sheet of intermediateproduct towards to the final product of functional film.

2-1. Manufacturing Sheet and Analysis

The sheet was manufactured by using hot press at 200° C. and 10 MPa,temperature and pressure conditions, respectively. LDPE resin for thesheet and the functional materials, PAPSS and ATPGAA selected throughthe experimental example 1, were used in the experiment. The particlesize of the two functional materials was adjusted to 1000 μm or less todistribute evenly in the LDPE resin.

In order to determine the quantity of functional material inmanufacturing the resin sheet, one of foods including absorbents, drylayer was chosen as a standard base. Based on the proper amount ofcommercially available absorbent, silica-gel, the needed quantities ofPAPSS and ATPGAA in case of they are applied were converted by comparingthe results of the experiment. The weight classification of the drylayer is shown in Table 7.

TABLE 7 A B C D company company company company product product productproduct total weight 15.51 g 14.10 g 13.47 g 12.12 g film weight 3.1 g3.17 g 3.16 g 3.12 g tray weight 4.21 g 4.27 g 4.25 g 4.50 g productweight 5 g 5 g 5 g 5 g Absorbent(silica- 8.2 g 6.66 g 6.06 g 4.5 g gel)weight

The average amount of silica-gel was 6 g according to the data shown inthe Table 7, and thus the amount of PAPSS and ATPGAA was calculated as1.7 g and 2.45 g, respectively. The amount of material for manufacturingthe sheet was determined under the assumption of 100% efficiency of thehygroscopic substances.

The dispersant was used to distribute the two powdery functionalmaterials into the resin layers. Triton X-100 was used as a dispersantfor the experiment as it's usually used to distribute powdery solidmaterials.

To evaluate the degree of dispersion by the amount of dispersant, eachsheet was manufactured, and the degree of distribution was identified byusing an electron microscope.

By using a TA.XT texture analyzer (stable Micro System Ltd, UK) thephysical properties of the prepared sheet were measured to evaluate thetensile strength and elongation (%). A load cell weighed 50 kg was used,and an average thickness of the sheet was 1.14±0.5 mm, and the samplesize was horizontally 1 cm×vertically 10 cm. Five (5) samples per oneexperimental group were manufactured and measured.

2-2. Results and Interpretation

The dispersion effect of Triton X-100 was visually confirmed prior tomanufacturing the sheet, and checked the amount of dispersant to preventthe dispersant from flowing out during the hot-pressing process.

The weight ratio of dispersant used to 1 g PAPSS was 1.5 times, 2.0times and 2.5 times.

The reason of using the dispersant in preparing the sheet is not only tohave dispersing effect of functional materials but also to eliminatealuminum foil (Al-foil) easily. The aluminum foil was used to supportthe experimental materials during the hot-press processes. The weightratio 2.0× and 2.5× amount of dispersants to 1 g PAPSS were effective.

The specific region of the sheet was selected and investigated byelectron microscopy at 2,400×. The results of the sheets used 2.5× and2.0× dispersants were shown in FIG. 5, and FIG. 6, respectively.

The parts indicated with numbers in FIG. 5 were expanded by electronmicroscopy and were shown in the right photos. The portions shown inblack in common were interpreted as the portions of PAPSS or dispersantaggregated. The L1˜L5 in number 1 section was the model and size of thematerial dispersed, and the average size of the parts except L5 was 7.09μm. In number 2 section, black spots around C2 were shown and the centerof the spot was donut-shaped.

That's a scratch form occurred in the press processing.

The material not dispersed surrounded the spherical resin formed a sheetby dissolving. The form shown in the number 2 section was observed inthe number 3 and 4 sections, and so it can be regarded as a feature ofpress processing. Overall dispersion was made in good condition.However, it can be interpreted as partially no dispersion was made sincethe black spot of PAPSS and aggregation by the liquid dispersant wereoccurred.

As shown in the electron microscope magnified photo of FIG. 6, the formembedded as in the FIG. 5 was hardly investigated but a wave patternobserved. It can be interpreted as the wave pattern occurred when thedispersed quantity was low since a small amount of dispersant wasdispersed by pressure but the dispersant still remained internally inthe sheet. That is justified that the material was in the wave pattern.

As a result of the investigation through electron microscopy, trials todisperse material by using a liquid dispersant seemed to be difficultdue to the aggregation occurred by contacting the liquid dispersant withpowder and following problems to manufacture the sheet. So it wasconcluded that the mechanical dispersion should be used.

Experimental results of physical properties of the sheet were shown inTable 8 and FIG. 7.

TABLE 8 average average max tensile elongation stress elongation tensilecomparision strength (%) rate (%) (kg/ml) rate (%) stress (%) LDPE 9.797.647 1.026316 97.2868 1.031579 — 9.9 101.486 1.026316 10.1 96.6871.052632 9.7 93.927 1.026316 9.7 96.687 1.026316 X 2.0 8.2 49.779 0.72355.4324 0.7922 56.98 76.94 (PAPSS) 10 77.952 0.881 8.7 50.155 0.761 8.949.638 0.777 9.3 49.638 0.819 X 2.5 10.2 63.671 0.897 63.3452 0.86865.11 84.14 (PAPSS) 9.3 57.342 0.816 10.2 66.661 0.897 10.5 67.781 0.9229.2 61.271 0.808 X 2.0 8.3 63.491 0.724 57.5698 0.7078 59.18 68.61(ATPGAA) 7.8 57.302 0.685 8 55.772 0.7 8.7 55.842 0.764 7.6 55.442 0.666X 2.5 6.2 56.912 0.54 57.1898 0.5848 58.74 56.69 (ATPGAA) 4.4 53.5120.385 6.7 54.732 0.59 8.3 63.491 0.724 7.8 57.302 0.885

Comparing the results of each sample based on the data of LDPE, theelongation rate showed from 50% to 60%, and the average tensile strengthrepresented 70% average. After the analysis, the sheet cut wasinvestigated. The cutting positions were different each other, howeverit was commonly observed that the cut occurred in the portion which thematerial was aggregated. Comparison depending on the amount ofdispersant was observed in PAPSS, and when the amount of dispersant washigh, it showed excellent results in terms of elongation and tensilestrength. It indicates that the dispersion affects eventually physicalproperties of film or sheet when physical mixings are conducted.

Experimental Example 3 Film Manufacturing

3-1. Film Manufacturing

As a result of experimental example of manufacturing sheets, thedispersion using a liquid dispersant was ineffective due to theaggregation occurred simultaneously when the powdery functionalmaterials were contacted. Therefore, a mechanical dispersion method wasselected. Materials were mechanically mixed with linear low densitypolyethylene by compounding until pallets obtained. After the firstdispersion of compounding to obtain the pallets, second dispersionthrough the twin-screw extrusion of the film was carried out.

Compounding was conducted by twin-screw extrusion (NIP Co., Wonju,Korea), and Hanwha 3126 (LLDPE for film) was used as a resin (Hanwhachemical Co., Seoul, Korea). The moisture absorbing materials, PAPSS andATPGAA were ground to 100 mesh particles using sieves to minimize theinfluence of physical properties by its particle size when manufacturingthe film.

The weight ratio of functional materials, PAPSS and ATPGAA to the palletwas adjusted to 10%. The temperature of twin screw extruder were set at150° C. for cylinder 1; 150° C. for cylinder 2; 160° C. for cylinder 3;170° C. for adapter; 170° C. for carrier, 170° C. for die 1, 170° C. fordie 2 under the 40 rpm velocity of the extrude kneader.

Pallets added with 10% functional material was manufactured to 0.7 mmthick film using a blow extrusion machine (ARTS film Co., Yang-san,Korea).

A total of 9 films including LLDPE, as a control, was manufactured atthe PAPSS and ATPGAA impregnation levels of 0.5%, 1%, 2% and 4% weightratio (FIG. 8).

The film weights are listed in Table 9.

TABLE 9 content(%) adsorbent(kg) LLDPE(kg) total(%) sample 1 0 — 10 10sample 2 0.05 0.5 PAPSS 9.5 10 sample 3 1 1 8 10 sample 4 2 2 8 10sample 5 4 4 6 10 sample 6 0.05 0.5 ATPGAA 9.5 10 sample 7 1 1 9 10sample 8 2 2 8 10 sample 9 4 4 6 10

In the manufacturing procedures, the samples of 2 to 5 comprising PAPSSshowed foaming tendency and the PAPSS foamed at 160° C. It was assumedthat the foaming occurred by the result of thermal decomposition ofPAPSS. Whereas, when the sheet was manufactured by using hot press inthe experimental example 2, no thermal decomposition phenomenon occurredwhen exposed at 200° C. for 5 minutes.

It is assumed that such phenomenon occurred due to the continuousthermal pressure stresses by the extruder in the manufacturingprocesses. On the other hand, ATPGAA appeared to be stable against theheat since it was a composite material of clay and polymer. It can beconcluded that ATPGAA has the characteristics of mixed feature havingthermal stability and stiffness of inorganic material with organicfunctionality as a hybrid material.

3-2. Evaluation of the Degree of Film Dispersion

The films of the above experimental example 3-1 were cut into eachspecimen of 0.25 m² area and 0.07 mm thickness to evaluate thedistribution degree of films (approximately 1 g of weight basis). Theevaluation and comparison was made by measuring the initial weight ofthe film specimen and the weight of each specimen measured after thedispersions made. The weight of each specimen was calculated under theassumption of 100% distribution was achieved. Results are shown in Table10.

TABLE 10 film weight(g)/ predicted adsorbent sample specimen weight (g)LLDPE(control) 1.159 ± 0.074 — 0.5% PAPSS 1.145 ± 0.092 0.006 ± 0.004  1% PAPSS 1.396 ± 0.139 0.014 ± 0.001   2% PAPSS 1.411 ± 0.141 0.028 ±0.003   4% PAPSS 1.188 ± 0.057 0.048 ± 0.002 0.5% ATPGAA 1.220 ± 0.0670.006 ± 0.002   1% ATPGAA 1.134 ± 0.064 0.011 ± 0.001   2% ATPGAA 1.149± 0.043 0.023 ± 0.001   4% ATPGAA 1.120 ± 0.046 0.045 ± 0.002

The degree of dispersion of the material can be predicted by the resultsof Table 10. When assessed based on the amount of 0.5% absorbentmaterial, the amount of functional material in the specimen was morethan the amount predicted. So, it was predicted that the functionalmaterial was well-dispersed in the manufactured films while comparingthe appearance of manufactured films each other.

In the comparison of dispersion functionality by the amount of ATPGAAand PAPSS, the relative difference between the amount of ATPGAA and thepredictive amount was smaller than that of PAPSS, and thus ATPGAA wasconsidered to have better dispersion functionality than PAPSS. In thedifference of film dispersion functionality of the material, it wasconsidered that the ATPGAA difference was caused in the manufacturingfilm processes by its polymer-based material characteristic unlike thethermal decomposition foaming properties of PAPSS at 160° C., if sameconditions were given. The viscosity of LLDPE solution was increased bythe thermal decomposition and foaming of PAPSS from the viscosity ofLLDPE solid particles through the mechanical distribution processes. Theincreased viscosity was considered as one of barriers against the filmdistribution.

3-3. Evaluation of the Film Sorption-Isotherm

The film samples of experimental example 3-1 above was cut into eachspecimen size of 10 cm of width×25 cm of length, and evaluated thesorption-isotherm using the same experimental method as in theexperimental example 1-1. The temperature was 20° C., and the durationperiod was 10 days. The other conditions were the same as theexperimental example 1-1.

Under the assumption of the absorbent was distributed 100% in the film,the amount of material was calculated (equation 2 below). Thesorption-isotherm of the film was measured by the calculation ofdividing the difference between the initial weight and final weight bythe amount of the material. Results are shown in Table 11 and FIG. 9

$\begin{matrix}{{Q_{eq}\left( {g/g} \right)} = \frac{W_{f}W_{i}}{W_{absorbent}}} & \left\lbrack {{Equation}\mspace{14mu} 2} \right\rbrack\end{matrix}$

TABLE 11 Qeq(g/g) 0.5% 1% 2% 4% % RH LLDPE PAPSS PAPSS PAPSS PAPSS 0.3090 0.003 ± 0.010 ± 0.008 ± 0.010 ± 0.005 0.004 0.002 0.002 0.384 0 0.014± 0.037 ± 0.029 ± 0.038 ± 0.007 0.007 0.002 0.004 0.514 0 0.156 ± 0.271± 0.254 ± 0.300 ± 0.018 0.017 0.039 0.017 0.610 0 0.141 ± 0.201 ± 0.219± 0.267 ± 0.013 0.014 0.026 0.017 0.731 0 0.222 ± 0.251 ± 0.317 ± 0.338± 0.020 0.016 0.032 0.007 0.879 0 0.327 ± 0.456 ± 0.504 ± 0.542 ± 0.0050.031 0.060 0.036 Qeq(g/g) 0.5% 1% 2% 4% % RH LLDPE ATPGAA ATPGAA ATPGAAATPGAA 0.309 0 0.003 ± 0.016 ± 0.014 ± 0.017 ± 0.005 0.004 0.001 0.0030.384 0 0.017 ± 0.066 ± 0.054 ± 0.058 ± 0.008 0.015 0.003 0.005 0.514 00.198 ± 0.502 ± 0.454 ± 0.511 ± 0.012 0.067 0.016 0.017 0.610 0 0.162 ±0.384 ± 0.379 ± 0.442 ± 0.015 0.026 0.023 0.017 0.731 0 0.248 ± 0.446 ±0.580 ± 0.549 ± 0.027 0.016 0.041 0.014 0.879 0 0.441 ± 0.697 ± 0.847 ±0.844 ± 0.011 0.080 0.063 0.052

FIG. 9 depicts the amount of adsorbed atmospheric moisture by 1 g ofPAPSS or ATPGAA impregnated to the LLDPE film. When comparing themoisture adsorption capacity of functional materials in FIG. 9, PAPSSshowed the best adsorption capacity. In case of functional materialsapplied film, decreased degree of moisture adsorption capacity wasdifferent each other at 20° C., as compared to those of functionalmaterials. However, the moisture adsorption capacity of PAPSS appliedfilm was lower than that of ATPGAA due to the thermal decomposition inthe manufacturing process of the film. ATPGAA impregnated LLDPE filmshowed lower moisture adsorption capacity than that of conventionalmaterial since LLDPE in functional film did a role of interference inthe moisture adsorption.

During the 10 duration days, the sorption-isotherm showed increasingtendency following to the concentration of functional materials added.The sorption-isotherm efficiency of the materials can be considered tobe same finally as the duration time becomes longer. However, it isestimated that the rate difference of the adsorption capability occurredat the 10th duration day is due to the rate difference of moistureabsorption speed of the two materials.

3-4. Comparison of Physical Properties of Films

Values of the tensile strength (TS) and elongation at break (EB) weremeasured to compare mechanical properties of the film by the quantitychange of PAPSS and ATPGAA in the films.

The thickness and size of samples were cut by horizontal 25 mm×vertical102 mm in accordance with ASTM D 3826 tensile strength standardspecifications, and measured by using TA.XT texture analyzer (stableMicro System Ltd, UK). The load cell was 50 kg, tensile speed was 500mm/min. Five or more samples were collected for each sample group andthe mechanical properties of those were measured.

FIGS. 11 and 12 showed the physical properties of functional film by theamount of applied absorbent. PAPSS applied film showed the change ofphysical properties depending on the amount increase of PAPSS. The filmsimpregnated PAPSS were equilibrated at about 68% of TS, as compared tothe control, LLDPE film. TS and EB values of the films impregnated withPAPSS of 0.5%, 1% and 2%, respectively, showed the numerical difference,however each deviation was small. It can be interpreted as the TSdecrease of the film is insignificant until 2% weight ratio of PAPSSadded. However, when 4% PAPSS added, the mechanical properties of TSdecreased to about 56% as compared to the control, LLDPE film.

When compared the changes of tensile strength (TS) by the addition ofPAPSS in FIG. 11 and ATPGAA in FIG. 12, the decrease rate of TS by theaddition of ATPGAA was relatively small. The foam phenomenon wasobserved by adding PAPSS in the film manufacturing, and so, it wasconsidered that the decrease of physical properties was furtherprogressed by the PAPSS pyrolysis at 160° C.

The EB shown in FIG. 11 showed a rapid decrease when 4% PAPSS was added.When 0.5%, 1%, 2% of PAPSS was added, the EB was decreased, however thedifference of EB decrease by the concentration (amount) of material wassmall.

The change of physical properties by addition of ATPGAA in FIG. 12 wassimilar with that by addition of PAPSS in FIG. 11. Comparing to thePAPSS impregnated films, TS was relatively high in the ATPGAAimpregnated films, however the EB values of ATPGAA impregnated filmswere lower than those of PAPSS impregnated films. ATPGAA is one ofclay-based inorganic materials and thus, assumed that the physicalproperties of polymer film are drastically decreased when excess amountof the material added. PAPSS is one of polymer based materials, andassumed that the chemical bonding is not occurred when adding excessamount of PAPSS but it places independently in the empty space of theresin matrix. Basically, the changes of physical properties of the filmsimpregnated with two materials are interpreted as the EB values areobtained by the differences of chemical structures of two materials.

3-5. Results

The evaluation results of adsorption capacities of films were shown inTable 12, specifically the adsorbed amounts of silica-gel, PAPSS, ATPGAAand those of 2% absorbent impregnated functional film were compared andshown in Table 12. The 2% absorbent impregnated functional film showedsmall changes of TS and EB values but high quantities of moistureadsorbed. Mutual comparison of the data by environmental conditions wasexpressed as percentage (%) per relative humidity. The moistureadsorption efficiency of 2% PAPSS impregnated film was maximum 33% ascompared to the original material PAPSS, however the PAPSS applied filmshowed similar or higher adsorption capacity in the relative humidity(RH) 50% or above conditions as compared to silica-gel. The moistureadsorption capacity of 2% ATPGAA impregnated film was more than that ofsilica-gel in the RH 50% or above environment.

TABLE 12 Qeq(g/g) proportion(%) silica-gel 2% PAPSS (C)/(B) × (C)/(A) ×% RH (A) PAPSS(B) film (C) 100 100 0.309 0.059 ± 0.046 ± 0.008 ± 18.36814.295 0.021 0.021 0.002 0.384 0.101 ± 0.130 ± 0.029 ± 22.477 29.0210.001 0.012 0.002 0.514 0.265 ± 0.908 ± 0.254 ± 27.948 95.703 0.0010.002 0.039 0.610 0.257 ± 0.671 ± 0.219 ± 32.570 85.049 0.001 0.0010.026 0.731 0.258 ± 0.935 ± 0.317 ± 33.878 122.751 0.010 0.004 0.0320.879 0.260 ± 1.620 ± 0.504 ± 31.124 193.621 0.021 0.020 0.060 Qeq(g/g)proportion(%) silica- 2% (C)/ (C)/ gel ATPGAA (B) × (A) × % RH (A)ATPGAA(B) film (C) 100 100 0.309 0.059 ± 0.067 ± 0.014 ± 21.537 24.3920.021 0.033 0.001 0.384 0.101 ± 0.124 ± 0.054 ± 43.312 53.339 0.0010.008 0.003 0.514 0.265 ± 0.515 ± 0.454 ± 88.244 171.313 0.001 0.0310.016 0.610 0.257 ± 0.350 ± 0.379 ± 108.199 147.404 0.001 0.014 0.0230.731 0.258 ± 0.487 ± 0.580 ± 119.002 224.829 0.010 0.024 0.041 0.8790.260 ± 1.033 ± 0.847 ± 81.938 325.097 0.021 0.084 0.063

ATPGAA and PAPSS are determined as the superior moisture absorbentswhich can replace silica-gel through the analysis of material selectionprocesses, film-application, physical properties of the films aftermanufacturing two material impregnated films, and moisture adsorptioncapacity evaluation. When the absorbent was applied in manufacturingfilms with the consideration of rates of physical property changes andadsorption capacity decrease, 2% weight ratio absorbent adding showed tohave a function of packaging products. Estimated that the moistureadsorption capacity of PAPSS decreased by PAPSS thermal-decomposition inthe extrusion process of manufacturing films. However, it only occurredpartially and loss of adsorption capacity of the whole film was notidentified.

Experimental Example 4 Analysis of Film-Packaged Seasoned Layer

4-1. Preparation of Packaged Seasoned Layer

The commercial seasoned layer covered by corn-oil was purchased fromSae-Chang Food Co. and used for this experiment. To evaluate the storageeffectiveness of the functional film applied package, the seasoned layersample was placed in a 5 mm thick, 8×10 cm polyethylene terephthalateplastic tray and then packed each tray with 12.5×20 cm test pouchfabricated inner layer with developed functional film (1^(st) packing)and outer layer with aluminum-coated film (2^(nd) packing) for thepurpose of blocking external environment. Prior to packaging, alldeveloped functional films were pretreated by placing them at 70° C. forone (1) week to remove any moisture resolved and adsorbed in the surfaceof the films. Experimental conditions were storing the packaged productat 23° C., 40° C., 60° C. respectively under 50% relative humidity and30 day duration.

The experiment was conducted with the commercially circulated seasonedlayer sample packed with silica-gel applied, as a control, same layersample packed with no silica-gel applied and same layer sample packedwith functional film impregnated with 0.5%, 1%, 2%, and 4% ATPGAA.

4-2. Peroxide Value (PV) Test

(1) Method

The peroxide value (PV) was calculated by the titration with 0.01Nsodium thiosulfate (Sam-chun pure chemical Co., Seoul, Korea) inaccordance with the method set forth in the Industrial Standards (KS H6019:2010).

Each seasoned layer sample was added to the mixed solution of 25 mL ofacetic acid and chloroform (3:2) and heated until dissolved. 1 mL ofsaturated potassium iodine solution and 30 mL of distilled water werethen added to the above solution of which the seasoned layer weredissolved enough, and allowed to store in the dark room for 10 minutes.Added starch solution as an indicator to the mixed sample and theperoxide value (PV) was determined by titration with 0.01 N sodiumthiosulfate. The volume of PV was calculated following to the equationbelow.

${PV} = \frac{\left( {a - b} \right) \times f \times 10}{S}$

Where,

a is the consumption volume of 0.01N sodium thiosulfate;b is the consumption volume of 0.01N sodium thiosulfate at blank test;f is the titer of 0.01N sodium thiosulfate;S is the sample weight.

2) Results and Interpretation

The PVs of seasoned layer packed with the functional films were shown inFIGS. 13, 14 and 15. The PVs of all samples were increased by longerstorage period and higher temperature. The seasoned layer sample packedwith silica-gel and the control of sample without silica-gel generatedhigher PVs than the samples packed with functional films.

However, there were no significant differences of PV among samples at23° C. and 40° C. The differences of PV among samples were significantat 60° C. The samples without silica-gel presented the highest peroxidevalue of 240.25±2.26 meq/kg on the duration day 24.

The seasoned layer sample packed with silica-gel presented the PV of190.55±5.10 meq/kg on the duration day 24. The seasoned layer samplepacked with functional films presented similar or less PVs as that ofsample packed with silica-gel. The seasoned layer packed with filmimpregnated with 0.5% ATPGAA presented 163.65±4.10 meq/kg at 60° C. onthe day 24.

Samples packed with functional films impregnated with relatively highconcentrations of ATPGAA presented relatively low PVs. Samples packedwith 4% ATPGAA film showed the PV of 155.84±3.31 meq/kg. The PVs ofsamples packed with functional films showed the difference by theconcentration of ATPGAA but the differences each other wereinsignificant.

The reason why the PV differences among samples packed with functionalfilms were insignificant is suspected that the moisture content in thepackage was eliminated concurrently when packed with the functionalfilms and so, only limited impact for the moisture to change lipidoxidation of the seasoned layer was available.

The tendency of PV decreasing was shown in the samples with silica-geland those with no silica-gel under the condition of 60° C. storingtemperature.

The PVs of all samples calculated on the duration day 20 at 23° C. wasover 40 meq/kg, the quality standard of seasoned layer specified in KS H6019:2010. Considering the general circulation period, six (6) months ofthe seasoned layer, it is estimated that the accelerated oxidationresult was due to either incomplete experimental pretreatment process ofnitrogen gas packaging being conducted commercially or exposing seasonedlayer samples to over 50% RH during the packing process of theexperimental environment.

4-2. Off-Flavor (Aldehyde and Ketone) Analysis

1) Method

The infrared spectrophotometer (FTIR spectrum, Perkinelmenr) was used todetermine the generation of off-flavor through storage and distributionprocesses. During the storage and experimental periods, monitoredwhether the rancidity of layer was occurred or not using ATR-FTIR sincethe rancidity is related to the production of off-flavor. For themonitoring, placed about 0.5 grams of the seasoned layer on the ATRplate and investigated it with the diamond crystal of FTIR.

The investigation was conducted by scanning four (4) times with 4000˜400cm⁻¹ spectra range. After one sample scanned, the ATR plate wascarefully cleaned with analytical grade acetone (Duksan Co., SouthKorea). Three spectra replicates were obtained for each sample.

Through the previously conducted PV experiment and its resultsinterpretation, identified that the generation and decomposition ofperoxide occurred simultaneously and, when decomposed, it transferred toaldehyde and ketone, the causes of off-flavor. Aldehyde and ketone peakvalues are represented indirectly as the ester carbonyl group oftriglycerides mainly by the FTIR spectrum range between 1800 cm⁻¹ and1700 cm⁻¹.

The generation degree of aldehyde and ketone can be determinedindirectly by the peak value reducing of ester carbonyl groupcorresponding area thereof since the ester carbonyl group was changed toaldehyde and ketone through fat oxidation.

2) Results and Interpretation

Fourier transform infrared spectroscopy (FTIR), a method to analyze fatsand oils, have advantages of requiring a brief sample pretreatmentprocess and being able to analyze non-destructive samples. The FTIR ismainly used to determine the degree of fat oxidation since it also cando a quantitative analysis and requires a short analyzing time (Dupuy etal., 1996; Lai et al., 1994; Rusak et al., 2003)

As shown in FIGS. 16, 17 and 18, the quantity of ester carbonyl grouptransferred to aldehyde and ketone during the storing period wasreduced. In the functional film applied sample group, the reducedquantity of ester carbonyl group was similar or less as compared tothose samples applied with silica-gel.

Overall, the initial spectrum absorbance value increased slightly andthen it decreased after six (6) storage days. It was identified that theinitial increase occurs due to the weakened interactive molecularstrength of ester carbonyl functional group (Sinelli et al., 2007).

4-3. Analysis of Texture (Fragility-Crispness)

1) Method

Seasoned layer in the market is produced by dry-roasting and addingedible salts for its taste to have marketability. Seasoned layer itselfadsorbs moisture when exposed to the moisture, and then it loses itscharacteristic fragile texture of crispness.

So, the texture fragility is an important criterion to evaluate itssensory quality and physicochemical quality changes. The fragility ofthe stored samples was determined by a texture analyzer (Stable MicroSystem Ltd., UK) equipped with a software program of tortilla chipsmethod, an exponent method to measure dry food fragility. Two probes of2 mm cylinder probe (Part No. P/2) and 35 mm cylinder probe (Part No.P/35) were used to measure. The compression in the system was measuredas newton force (N) at a speed of 60 mm/min and the load cell of 50 kg.

2) Results and Interpretation

The fragility of seasoned layer was closely related with the moistureexisted in the package and the results are shown in FIGS. 19, 20 and 21.

During the initial storage period, the fragility value was 0.56 N. Onthe storage duration day 30 under 60° C., the fragility value of theseasoned layer sample packed with 0.5%, 1%, 2%, 4% ATPGAA impregnatedfilms was increased to 0.66N, 0.65N, 0.64N, 0.61N, respectively ascompared to 0.57N, the value of the control, sample group packed withsilica-gel. The fragility (crispness) of seasoned layer sample packedwith 4% ATPGAA impregnated films at 60° C. was increased in thisexperiment.

The results can be interpreted as the increase of fragility of seasonedlayer occurred by the elimination of moisture dissolved on the surfaceof seasoned layer at the 60° C. storage temperature and that the ATPGAAimpregnated in the packaging film absorbed the moisture existed insidethe film, and thus the drying of seasoned layer was progressed duringthe storage period.

Seasoned layer packed with the developed functional film showedrelatively better fragility as compared to that packed with silica-gel.It is because the amount of adsorbed moisture in ATPGAA-impregnatedgroup was higher than that of silica-gel (the amount of silica-gel usedwas 1 g, and that of ATPGAA was different by the concentration ofATPGAA, in case of 4% of ATPGAA, the amount of ATPGAA used wasapproximately 0.12 g).

The fragility of the control group with silica-gel at 60° C. wasincreased by the length of storage period. It is estimated that theincrease of the control group occurred due to the high storingtemperature can be affected by the moisture-absorbance of silica-gel aswell as lipid oxidation during storage.

4-4. Color Change

1) Method

Color of seasoned layer was measured in terms of values of hunter L, a,and b using color-difference meter (Model CR-100, Minolta Co., Japan).The values of L, a, and b were further converted into total colordifference (ΔE=√{square root over (ΔL²+Δα²+Δδ²)})

2) Results and Interpretation

The changes of color parameters, Hunter L, a, b, of seasoned layerpacked with different packaging films during its initial and terminalstorage periods were shown in Table 13.

L value was decreased during storage, and the decrease of ΔL valuereflected the darkening of color.

The seasoned layer showed an increase of Δa and Δb values duringstorage. The seasoned layer packed with the control film withoutsilica-gel showed higher value of ΔE as compared to those packed withthe functional films (FIG. 22), and the seasoned layer packed with thecommercial package film containing silica-gel also showed relativelyhigher value of ΔE. It can be estimated that the present developedfunctional films have more effective moisture absorbency than silica-gelin sachet. The result indicates that the removal of the moisture contentin seasoned layer may reduce its color change and oxidation duringstorage.

TABLE 13 the color changes of seasoned laver on the day 30 Commercialfilm Temperature Commercial film (without silica- Concentration ofATPGAA in film structures (° C.) (with silica-gel) gel) 0.5% 1% 2% 4%23° C. ΔL −6.412 ± 0.050 −6.195 ± 0.100 −5.047 ± 0.200 −5.318 ± 0.050−5.074 ± 0.050 −5.074 ± 0.050 Δa  2.746 ± 0.050  2.988 ± 0.000  2.255 ±0.050  1.872 ± 0.100  1.265 ± 0.035  1.265 ± 0.066 Δb  4.588 ± 0.142 4.559 ± 0.000  4.415 ± 0.042  4.415 ± 0.000  4.492 ± 0.058  4.236 ±0.058 40° C. ΔL −5.675 ± 0.002 −6.204 ± 0.102 −5.602 ± 0.300 −4.985 ±0.098 −4.965 ± 0.393 −5.051 ± 0.346 Δa  3.653 ± 0.066  3.538 ± 0.058 3.665 ± 0.000  3.540 ± 0.000  3.358 ± 0.000  3.359 ± 0.050 Δb  4.706 ±0.144  5.016 ± 0.001  5.232 ± 0.043  4.869 ± 0.000  4.933 ± 0.008  4.869± 0.016 60° C. ΔL −4.660 ± 0.104 −5.235 ± 0.185 −5.141 ± 0.050 −4.631 ±0.046 −4.561 ± 0.484 −4.452 ± 0.340 Δa  5.397 ± 0.000  4.795 ± 0.016 5.095 ± 0.103  4.938 ± 0.042  4.579 ± 0.008  4.419 ± 0.050 Δb  4.131 ±0.045  3.392 ± 0.005  4.567 ± 0.044  4.416 ± 0.044  4.374 ± 0.000  4.240± 0.016

4-5. Weight Change

1) Method

Seasoned layer itself absorbs moisture if there is no other element toadsorb moisture in high water activity environment. The weight change ofseasoned layer was measured to determine the moisture adsorptivecapacity. The weight of seasoned layer was measured using a digitalbalance (Sartorius Ag Gottingen, Germany).

2) Results and Interpretation

Weight changes of seasoned layer were presented in FIGS. 23, 24 and 25.At 40° C. and 60° C. the total weight loss was observed in the seasonedlayer packed with all films on the day 3. It is probably that themoisture in the seasoned layer adsorbed from the outside environmentduring the preparation of packaging samples was vaporized into theatmosphere surrounding the product in the package at the hightemperatures.

On the day 15, the weight of seasoned layer packaged with silica-gelbegan to increase at 23° C., 40° C., and 60° C. This can be attributedto the moisture of seasoned layer absorbed from the headspace in thepackage during storage. There were no clear differences between theATPGAA impregnated films and the commercial package containingsilica-gel in the seasoned layer sachets.

4-6. Sensory Evaluation

1) Method

Sensory evaluation was carried out with the experimental samples at 40°C. The quality attributes of color, taste, texture fragility,off-flavor, and overall acceptance were evaluated by twenty untrainedpanelists participated in the department of packaging. The score ofevaluation was determined a 9-point hedonic scale. These parameters werescored with 9 for extremely like and 1 for extremely dislike, except foroff-flavor. Off-flavor was evaluated as 9 for very strong and 1 forleast off-flavor.

2) Results and Interpretation

The sensory evaluation was conducted with samples stored at 40° C.during two months because the experimental results with samples storedat 23° C. presented the difference of scientific qualities indistinctly.The results were shown in Table 14. The result showed no significantdifference among samples by considering off-flavor, fragility, color,and overall acceptance. High concentration of ATPGAA impregnated filmwas effective for no decreasing of sensory quality by the action ofabsorbing excessive moisture. The developed functional films presentedeffectiveness for maintaining sensory quality under the oxidationaccelerated condition. It means that application of developed functionalfilm in seasoned layer packaging may extend its shelf-life in the marketand increase the stability of quality because packed seasoned layer ispossibly exposed to the temperature accelerated condition of 40° C. insummer.

TABLE 14 the sensory evaluation results with sample stored at 40° C.No.1 No.2 No.3 No.4 No.5 No.6 Off-flavor  3.727 ± 2.611^(a)  5.000 ±2.408^(a)  4.545 ± 2.252^(a)  3.818 ± 2.183^(a)  5.000 ± 2.683^(a) 4.364 ± 2.292^(a) Fracturability  5.909 ± 1.921^(a)  5.455 ± 1.368^(a) 6.364 ± 1.206^(a)  5.091 ± 1.044^(a)  5.818 ± 1.537^(a)  6.727 ±1.348^(a) Color  5.636 ± 2.206^(a)  4.909 ± 1.375^(a)  5.909 ± 1.446^(a) 5.455 ± 1.368^(a)  5.364 ± 1.362^(a)  6.636 ± 1.120^(a) Taste  5.727 ±2.901^(ab)  4.636 ± 1.748^(ab)  5.455 ± 1.968^(ab) 5.091 ±  4.364 ±1.912^(ab)  5.636 ± 1.690^(ab) 11.514^(ab) Overallacceptance  5.000 ±1.789^(a)  5.000 ± 1.549^(a)  5.727 ± 1.489^(a)  5.000 ± 1.000^(a) 5.545 ± 1.695^(a)  6.182 ± 1.328^(a) ^(a-b)Means with different letters(a-b) within the same row at same material are significantly differentby Duncan's multiple range (p<0.05) *No.1: Commercial film (withsilica-gel) No.2: Commercial film (without silica-gel) No.3: 0.5% ATPGAAimpregnated film No.4: 1% ATPGAA impregnated film No.5: 2% ATPGAAimpregnated film No.6: 4% ATPGAA impregnated film

POSSIBLE USES IN INDUSTRIES

According to the present invention, packaging films having excellentmoisture absorbing function and physical properties can be manufactured.Generally exporting flowers in floral business are packed with silicagel and moisture absorbing paper to maintain the colors of flowers. Byreplacing the packing paper with the functional film manufactured by thepresent invention which is handy to use and highly effective to absorbmoisture, the effective maintaining of product quality may increase. Itmay be applied to especially moisture sensitive dry foods such as flour,frying powder, dry fish, and the like, and also can be used effectivelyin storing machine parts or used metals to improve the quality ofstoring products. It also can be used for packaging material for thestoring products and to absorb moisture in the storing warehouses.

Present invention provides the resin composition of seasoned layerpackaging films to maintain the quality of seasoned layer by eliminatingthe moisture adsorbed inside the packaged film.

What is claimed is:
 1. Resin composition for moisture absorbing filmscomprising polyethylene resin, and as a moisture absorbent, polyacrylicacid partial sodium salt (PAPSS) or attapulgite synthesized acrylicamide (ATPGAA).
 2. The resin composition of claim 1, wherein the weightratio of moisture absorbent to total weight of resin composition is from0.5% to 4%.
 3. The resin composition of claim 1, wherein thepolyethylene resin is characterized by linear low density polyethylene(LLDPE).
 4. The resin composition of claim 1, wherein the polyethyleneresin has a melting point between 150° C. and 180° C.
 5. Moistureabsorbing film manufactured with the resin composition of claim
 1. 6.Manufacturing method for moisture absorbing packaging film ischaracterized by: The pallet manufacturing step of compoundingpolyethylene resin and a moisture absorbent added; and steps of addingpolyethylene resin to the pallets obtained above and conductingblow-extrusion to compress them, wherein the moisture absorbent to beused is a polyacrylic acid partial sodium salt (PAPSS) or attapulgitesynthesized acrylic amide (ATPGAA).
 7. The characterized method of claim6, wherein the step of manufacturing pallets, the weight ratio range ofpolyethylene resin to the moisture absorbent is from 20:1 to 20:6,wherein the step of blow-extrusion, the quantity of polyethylene resinto be added further is to provide the weight ratio of the moistureabsorbent to total resin composition is from 0.5% to 4%.
 8. Thecharacterized method of claim 6, wherein a grain size of the moistureabsorbent is from 100 mesh to 500 mesh.
 9. The moisture absorbingpackaging film of claim 5, wherein the attapulgite synthesized acrylicamide (ATPGAA) is used to prepare the moisture absorbing film, and themoisture absorbing film is for packaging products.